RPM packages can have preinstallation, postinstallation, preuninstallation, and postuninstallation scripts. These are scripts that the rpm command will execute before and after installing a package, as well as before and after removing the package. The --scripts option to the rpm –q command lists the scripts associated with a package. The basic syntax follows:

rpm -q --scripts package_name

For example:

# rpm -q --scripts tcsh

postinstall scriptlet (through /bin/sh):

if [ ! -f /etc/shells ]; then

echo "/bin/tcsh" >> /etc/shells

echo "/bin/csh" >> /etc/shells

else

grep '^/bin/tcsh$' /etc/shells > /dev/null || echo "/bin/tcsh" >> /etc/shell

s

grep '^/bin/csh$' /etc/shells > /dev/null || echo "/bin/csh" >> /etc/shells

fi

postuninstall scriptlet (through /bin/sh):

if [ ! -x /bin/tcsh ]; then

grep -v '^/bin/tcsh$' /etc/shells | grep -v '^/bin/csh$'> /etc/shells.rpm

mv /etc/shells.rpm /etc/shells

fi

PRODUCTION: NOTE THE “fi” on a line by itself at the end of this listing. Thanks, -Eric

The simple scripts shown here add an entry to the /etc/shells file and clean up the entry when uninstalled.

Cross Reference

Cleaning up any changes your package makes on uninstallation is a very good idea. See the chapters in Part II, Creating RPMs, for details on making your own well-behaved packages.

Other packages have more complex scripts, as shown following:

# rpm -q --scripts sendmail

preinstall scriptlet (through /bin/sh):

/usr/sbin/useradd -u 47 -d /var/spool/mqueue -r -s /dev/null mailnull >/dev/null

2>&1 || :

postinstall scriptlet (through /bin/sh):

#

# Convert old format to new

#

if [ -f /etc/mail/deny ] ; then

cat /etc/mail/deny | \

awk 'BEGIN{ print "# Entries from obsoleted /etc/mail/deny"} \

{print $1" REJECT"}' >> /etc/mail/access

cp /etc/mail/deny /etc/mail/deny.rpmorig

fi

for oldfile in relay_allow ip_allow name_allow ; do

if [ -f /etc/mail/$oldfile ] ; then

cat /etc/mail/$oldfile | \

awk "BEGIN { print \"# Entries from obsoleted /etc/mail/$oldfile

\" ;} \

{ print \$1\" RELAY\" }" >> /etc/mail/access

cp /etc/mail/$oldfile /etc/mail/$oldfile.rpmorig

fi

done

#

# Oops, these files moved

#

if [ -f /etc/sendmail.cw ] ; then

cat /etc/sendmail.cw | \

awk 'BEGIN { print "# Entries from obsoleted /etc/sendmail.cw" ;} \

{ print $1 }' >> /etc/mail/local-host-names

cp /etc/sendmail.cw /etc/sendmail.cw.rpmorig

fi

#

# Rebuild maps (next reboot will rebuild also)

#

{ /usr/bin/newaliases

for map in virtusertable access domaintable mailertable

do

if [ -f /etc/mail/${map} ] ; then

/usr/bin/makemap hash /etc/mail/${map} < /etc/mail/${map}

sleep 1

fi

done

} > /dev/null 2>&1

/sbin/chkconfig --add sendmail

preuninstall scriptlet (through /bin/sh):

if [ $1 = 0 ]; then

/etc/rc.d/init.d/sendmail stop >/dev/null 2>&1

/sbin/chkconfig --del sendmail

fi

postuninstall scriptlet (through /bin/sh):

if [ "$1" -ge "1" ]; then

/etc/rc.d/init.d/sendmail condrestart >/dev/null 2>&1

fi

exit 0

In this case, the main script is the post-install script, which tries to convert old-format data into the new format, thereby helping users upgrade to the newer release.